Uliuui LciHl/c ui i/ujimiuu apaota—otit&Lo, jjaiivo, ajuu m^ nivt,—aiivi v-»x tjiw uj.,.^-...-» relationships among uses; i.e., the planning of employment, residences, transportation routes, etc. so as to minimize costs and congestion and to maximize amenities and conveniences. The growing size of modern cities, the increase of automobile traffic, plus the growth of slums, congestion, and disorder attest to the need for increased attention to planning for orderly city growth in developed and less developed countries alike. Indicators of Pollution The two general indicators of pollution sources, or latent environmental degradation, are population density (especially urban population) and gross national product (GNP) per capita (which is generally a result of industrialization). As a country or region moves toward higher levels in these two respects, it becomes increasingly likely to undergo environmental deterioration (air and water pollution, solid waste disposal problems, crowding, etc.) unless countervailing measures are taken to prevent or abate these harmful effects on the environment. In Table 3 we have gathered some of the indicators of pressures on the natural environment for a wide cross-section of developed and less developed countries, and for all the developed countries, and for the less developed countries taken together (except the communist nations). In the first set of columns are population density, urbanization, and gross national product. Population density and GNP are calculated in relation to agricultural area as well as to total area of each country, in order to show pressures on land that is more intensively used. Mere surface area has limited relevance to either production or pollution problems, especially for such countries as Egypt, Brazil, and Australia. It can be seen that, contrary to Malthus' thesis, there is little if any correlation between population density and levels of income. Although incomes are low in densely populated countries like India and the Philippines, equally low incomes are found in countries with low population densities, such as the Congo or Brazil; moreover, some of the highest income levels are in the countries with the greatest population densities, such as Japan and the Netherlands. The last two lines of Table 3 show that there is no overallctricity, and transportation have been the principal detractors from air quality. In some American cities the motor car is charged with producing as much as 80 percent of the total air pollution. In other areas, the principal polluters are ore smelters, blast furnaces, pulp mills, or steam plants for generating electricity. A quick index of overall air pollution is the consumption of mineral fuels, although the degree of impact depends on specific local conditions, including theof raising difficulties with "quality."s 143-148), although in most cases they appeared to be incomplete.